SSDs may be used instead of a hard disk used in a computer or a mini hard disk used in a portable device. The SSDs use devices such as flash memories, and store data so that the SSDs may implement programs quickly, and shorten a boot time compared to a hard disk when the SSDs are used as a booting disk. Before shipping the SSDs, they should be tested to distinguish defective SSDs (e.g., rejects) from non-defective SSDs.